Control of broadcasting by keys



M 1 I A. D. TRENOR 1,712,181

CONTROL OF BROADCASTING BY KEYS Filed Nov. 31. 1922 s Sheets-shes; 1 v

May 7, 1929. A. D. TRENOR common pf! BROADCASTING BY KEYS- Fil ed Nov. 21, 1922 3 Sheets-Sheet 2 awbe/ ntoz 0. 72*2/20/2 May 7,1 1929. A. D. TRENOR v I "1,712,181

) CONTROL OF BROADCASTING BY KEYS I I Filed Nov. 21. 1922 3 Sheets-Sheet 3 anomtoz Patented May 7, 1929.

UNITED STATES PATENT" OFFICE.

counter. or BRoA npAsrme Biz KEYS. I

Application filed November 21, 1922. Serial No. 602,378.

This invention. relates to improvements in methods of and means for controlling the dissemination of information, music, etc, from broadcasting stations, and more particularly to the selective reception thereof.

Some of the objects of the present invention are to provide a receiving station selectively responsive to the energy emitted by a broad casting station; to provide means for tuning the receiving station to desired frequencies; to provide means for automatically controlling the tuning means in accordance with varying combinations of frequency characteristics of the transmitted energy; to provide portable apparatus which may be used in combination with the receiving station to control the tum ing thereof; to provide a plurality of devices operable together to determine. principally the responsiveness of the receiving station; and to provide separable means for placing the devices in dctinite positions determined by the term of the particular separable means employed. I

Other objects will appear from thei'ollowing description taken in connection with the accompanying drawings and from the appended claims: I I

Fig. 1 is a diagram of the circuit connec tions of a receiving station embodying the invention;

Fig. 2 is a rear view ot-the receiving station with the rear cover removed; Fig. 3 is a section taken on the line 3-3 of Fig. 2;

Fig. 4. is a top view partly in section of a modified form of the invention;

Fi g. 5v is a rear view partly in section of the en'ibodiment of the invention shown in Fig. 4; Fig. 6 is a view in transverse section of one of the condensers shown in Figs. 2 and 4; and Fig. 7 is a front view of the dials associated with the condenser.

The system of the present invention may in clude a secret system of comn'iunication 0t radiant energy of any desired form.

The sending station of the system transmits a carrier wave of relatively high frequency upon which there is impressed one or more series of amplitudevariations having a relatively lower but supersonic frequency and modulated byvoice or other signal currents. The signal currents may be of any desirecL character as, for example, broadcasted music,

lectures, etc.r, such as are disseminated from ALBERT I). TRENOR. GLOUCESTER, MASSACHUSETTS, ASSIGNOR TO JOHN H AYS HAMMOND, {IR- OF GLOUCESTER, MASSACHUSETTS.

warthc signals may be of the nature of secret lnstructions intended to be received only by certain agents provided with special apparatus enabling them to adjust receiving stations therefor. The receiving station of such a secret system may be described as comprising a plu- Rassuu) mil- 9 1942 I so-called broadcasting stations. In time of 55 rality of resonant elements connected in series and tuned to the carrier frequency and to the i'requency of the periodic variations respectively, so as to be selectively responsive to the energy received from the sending station with which the receiving station is arranged to co-ope rate and thereby enable the received energy to be transformed into sensible manifesta tion's.

Referring to the drawings, Fig. 1 illustrates one form of receiving apparatus embodying the present invention. As shown, there is provided a. receiving element such as an antenna 10 positioned to intercept Hcrtzian waves. The circuit of the antenna 10 includes an inductance 11 con led to a closed, oscillatory circuit 12. The c osed, oscillatory circuit '12 comprises an inductance 13 and a variable condenser 14 and is tunedtoresonam-e with the carrier frequency of the oscillations received by the antenna '10. 'lheclosed, oscillatory. circuit 12 is operatively connected to the input of a detector which may take the form of a thermionic device 15 having a tilamcnt 16 for emitting electrons, a plate 17 upon which'the electrons impinge and a grid 18 for controlling the passage of the electrons.

, For heating the filament 16 of the thermionic device, thereuis provided. a' suitable filament battery 20. A rheostat 21 is connected in series with the filament 16 and the bat-.

tery to enable the intensity of'the heating current to be controlled. In shunt with the battery 20 is a potentiometer 22 having a slider 23 connected to the closed," oscillatory circuit .12, whereby the normal potential of the grid 18 with respect to the filament may be adjusted. A high voltage battery 24 is connected in series with an inductance 25 and a pairof contact springs 26 and 27 t0 the plate 17 of the thermionic device 15, and thus the plate 17 is maintained at a positive potential with respect to the filament 16 of the device 15. A'by-pass condenser 28 is provided in shunt with the inductance 25.

For tuning the receiving station to the frequency of the periodic variations impressed upon the emitted energy to which the station is intended to be responsive, there is provided a second, closed, oscillatory circuit 30 comprising an inductance 31 inductively coupled to the inductance and a variable condenser 32. The closed,-oscil latory circuit is operatively connected to the input of a second detector which may take the form of a usual, three-electrode, thermionic device 33 having a filament, grid and plate. The filament of the device 33 may be heated by the same battery 20 which serves to supply current to the filament of the first-mentioned thermionic device 15, a suitable rhcostat 34 being provided for controlling the strength of the current. In shunt with the battery. 20, there is provided a potentiometer 35 having a slider 36 connected to the closed, oscillatory circuit 30 whereby the normal potential of the grid of the device 33 with respect to the filament thereof may be adjusted. The output circuit of the device 33 includes a pair of contact springs 37 and 38 in series, a suitable indicating device such as a telephone receiver'39 I having a by-pass condenser 40 in shunt therecapacity.

with, and a connection 41 extending to the positive terminal of the plate potential battery 24. The contacts 26, 27 and 37, 38 are constructed and arrangedso as to be normally out of engagement with one another and to be brou 'ht into contact in pairs as shown in Fig. 1 'hy means of a separable member or key 42 for a purpose which will be subsequently set forth.

For making close or accurate adjustments of the receiving apparatus, there may be pro vided in parallel with the condenser 14 an auxiliary condenser 42 of smaller capacity and in parallel with the condenser 32 a second auxiliary condenser 43 of relatively small The apparatus-of Fig. 1 may be enclosed in compact form in a casing (see Figs. 2 and 3) having mounted therein the inductances, condensers, thermionic .devices and associated apparatus of Fig. 1. The indicating device 39 is connected with the remaining apparatus by means of a suitable, flexible cord so that itmay be held in desired position apart from the casing. Such parts of the receiving station apparatus as are to be adjusted for the purpose of tuning may be arranged for adjustment-by the rotation of suitable shafts associated therewith. While.

' shownin "the present embodiment being of the usual sector type in which a plurality of semi-circular plates 51 are held in fixed position and a plurality of semi-circular plates 52 The sleeve 53 is loosely mounted on a shaft 54 having on its innerend a pinion 55. The sleeve 53 1s ourn'alled 1n the casing 50 and a partition 55 therein.

' For indicating the position of the'sleeve 53 and the capacityof the condenser 32, there is provided a knob o nhandle 60 having a pointer 61 and affixed to the sleeve 53 outside of the casing 50 in any suitable manner, as by a screw 62. A second knob 63 is keyed to the shaft 54 and is provided with a shoulder 64 engaging a surface of the knob 60 and the end of the sleeve 53. The sleeve 53 and knob 60 may be adjustably positioned with respect to the shaft 54 and knob 63 and may be maintained in any dcsired'position relative thereto by means of a'lock nut 65 which may be operated to hold the knob 63ain intimate contact with the knob 60 and sleeve 53. The knob 63 is provided with a pointer 66 for indicatin g the relative adjustment of the shaft 54 and sleeve 53, and the pointer-61may be arranged to co-operate with a series of calibrations marked on the front of the casing 50, as shown in Fig. 7 to indicate the position of adjustment of the condenser 32.

5 For operating the pinion 55 there is provided a longitudinally movable rack 70. The shaft of this rack moves through suitable hearings in parallel frame members 71 and 72.

rack shaft 7 0 between the frame member 71 p and a'collar 73 rigidly secured to the rack shaft serves to maintain its'end 74 securely seated in the slot 75 of the key 42.

Similarly, the other elements of the receiving station apparatus which are to be ad'- justed are actuated by racks 170, 270 and 370, the parts associated with these racks being designated by numerals having the same tons and units digits as are applied to the parts coacting with the shaft 70 and being operated in a similar manner.

For raising the rack shafts 70, 17 0, etc., in order to permit entry of the key 42, there is provided a perforated plate slidably mounted-on a pair of rods 81 and arranged to engage the collars 73, 173, etc., on the respective rack shafts. The plate 80 maybe reciprocated by a crank 82 connected therewith by curved links 83 pivotally secured to arms 84 fast on the shaft of the crank 82. The shaftof the crank 82 is journalled in suitable bearing blocks 85 in a well known manner.

' A pawl 86 is pivotallymounted on the casing 50 and held in engagement with a notch 87 v in the key 42 tomaintain the key 42 in operative position independently of the ends 74 174, etc., of the rack shafts.

For operating the contact springs 26, 27 and 37, 38, the key 42'is provided with an extension 90 having a shoulder 91. The extension 90 serves to throw the contact spring 27 into engagement with the contact spring 26, and the shoulder 91 co-operates with the contact spring 38 to throw it into engagement with the contact spring 37 In the normal position of the contact spring 38, when no key 42 is inserted, it engages contact spring 92. The key 42 is provided with slots corresponding' in number to the number'of racks and pinions to be operated, the'depth'of each slot determining the operative position of the corresponding rack and pinion In the present disclosure, the two slots 7 5, 17 5 are used in combination for adjusting the same resonant circuit 30, the slot 75 determining roughly. the capacity which is to be usedand the slot 175 determining the capacity more precisely and thus more accurately tuning'the circuit. In the operation of the embodiment of the invention shown in Figures 1, 2 and 3, the

sendingstation emits energy having a lie culiar wave form to which the usual type of receiving station is not responsive. The rcceiving station shown diagrammatically in Fig. 1' may, however, be turned thereto" and such tuning may be accomplished in accordance with the present invent-ion by the use of a portable, separable member such as the key 42 having slots 75, 175, etc., cut therein. The depths of the slots are determined by the wave characteristic of the energy emitted during a 'iven performance, keys of unlike character eing supplied for different performances. V The crank 82 is turned to raise the racks 70, 170, etc., and the racks are maintained in raised position while the key 42is inserted until the detent 86 engages the notch 87. The insertion of the key actuates the contact springs 27 and 38 to open the circuit through the contact 92 and close the circuits through contacts 26' and 37 respectively. Upon release of the crank 82, the rack shafts 7 0, 170, etc., move downwardly under control of their retractile springs and enter therespective slots in the key 42. This downward movement causes rotation of the respective pinions 55, 155, etc., the shafts 54, 154, etc., and

the sleeves 53, 153, etc. clampedthereto. R0- tation of these sleeves causes a, change'in' the effective capacities ,of the respective condensers in the embodiment selected for illustration or in the inductance or other desired characteristic of other forms of apparatus which may be used for tuning. Y

The key may be released by rotating the crank 82 and operating the detent 86 and may then-be withdrawn The apparatus may be adjusted to compensate for wear, absorption of moisture or other effects by loosening the lock nut and changin the position of the knob 63 with respect to t e knob 60. Corrections may then be made in the setting of the apparatus as controlled. by a given key com bination. 1

- When the key is inserted, the plate circuits of the thermionic devides 15'and 33 are closed I by contact springs 26., 27 and 37, 38 respective 1y. The'circuit of the battery 20 may alsobe for adjusting the condenser 14 will be hereindesignated condensers of Fig. 1. The means after described, and it will be understood that, as shown in Fig. 4 of the drawing, similar means maybe provided for adjusting the condenser 32. Themovable plates of the con- .denser 14 are fixed to a rot-atable sleeve' 353 having a'hub 401 of enlarged. diameter adjacent to the partition 55". Amopen receptacle 402, which, as shown, is rectangular in form,

socket for a separable member 442 of similar shape. 1 The inner face of the member 442 is provided'with a plurality of recesses in which are positioned a corresponding plurality of cylindrical members 47 5. The member 442 is preferably constructed 1, of fragile material, such as p'orcelain'or thelike, and is provided with a face plate 403 of brass or other metal for maintaining the-cylinders 475 inposition.

The operating shaft 354 of the condenser .14

.has a pin 404 extending laterally therefrom,

-' is secured to the partition 55' and serves as a I ample, the groove of a cylinder 475 may be cut straight inwardly or may be curved spirally in either direction. In the latter case, the direction of curvature, that is", to-the right or to the left and the degree of curvature determine the setting of the apparatus associated with the shaft controlled by the cylinder. It will be seen that the separable member 442 is so constructed that inspection thereof will not indicate the -combination for which it is intended, and since the member is made of fragile material any attempt to dis-assemble the same will result in its entire destruction.

I For centering the separable control member 442 and for actuating the-circuit controlling contact springs,there is provided a pair of pins 406. and 407 fixedly mounted onthe member 442 and co-acting with the springs 27 and 38 respectively. I Detents 408 and. 409,

maintain the member 442 in locked position L with-in the-receptacle 402. In the operation of the form of the invention illustrated in Figures 4 and 5, the sep 'a'rablelmember 442 is, inserted in the receptacle 402 and locked therein by means of detents 408 and 409. The insertion of the separable member 442 in the receptacle 402 causes rotation of the shafts of the condensers 14 and 32 or other'desired'shafts into a predea termined combination of positions according to the depth and direction of rotation of the curves 405 of the cylinders 475, and thus the receiving apparatus-is automatically tuned according to the key combination. When it is deslred to remove the separable member 442, the detents 408 and 409 are depressed and the member may then be withdrawn.

The invention upon which this application is based is broader than thd specific embodiments shown and described. for the purpose of illustrating some of the ways in which it may be employed. The scope of the invention is therefore understood notto be limited bythe present specificdescription. I intend y no limitations other than those imposed. by

the appended claims.

What I claim is:

1. A receiving apparatus for radiant. en-

ergy comprising tuning means, a plurality of devicesfor adjusting the tuning means and a. key. for determining the positions 'of said a separable membei'g'having, a different form 40' devices in accordance with the form of-the key to tune-the apparatus'to energy desired to be received.

2. A receiving apparatusjfor radiant energy comprislng tumngmeans, a pluralityof devices for ad ust1ng the tuning means and in its various portions, for independently determining positions of said-devices in accordance with its form atsaid various portions. V

. 3. A receiving apparatus for radiant energy comprising tuning means a plurality of rotatable shafts for adjusting the tuning means, and means for operating .said shafts to tune the receivinga'pparatus to energy desired to be received, comprising a separable .m'ember having portions operable to cont-r01 v the positions of said shafts independently in accordance with the forms of said different portions} v V 4. A'receiving apparatus for radiant ene1 'gy comprising a casing, tuning means,

members mounted on theeasing for to and fro movement and operatlvely connected with the tuning means, means for operatingby said members.

5, A receiving "apparatus for radiant 'energy comprising tuning means, a plurality of.

members operatively connected with difier- 4 tion, a key insertable in thepaths of movement 9f said members and operable to limit the movements of said members in the opposite diretion and thereby determine the ad justnients of the tuning means in accordance with the form of the lgey at the portions engaged by said members.

6. A receiving apparatus for radiantenergy comprising tuning means, a plurality of.

independently operable members operatively connected with thetuning means,means fpr yieldingly movingsaid members, manually operable means for moving the members in' 7 opposition to said yielding means, 'a key in sortable in the paths of] vement of said members and havingindent'ations constructed to receive said members,so that the movements of said members under the action of said yielding means and, consequently, the

adjustments of the'tuning means. are deter-1 -1'nined by the depths of the indentations in said key. i .7, An apparatus for receiving radiant en- 'efit elements of the tuning means, common .j I means for moving said members 1n one d recergy having a high carrier frequency and"- having periodic variations impressed thereon of a frequency lower than said 02111161,f16

quency but above good audibility, comp'risv ing circuits connected together in'cascade red .lation, a detector interposed-between said cir;

cuits and means for tuning said circuits respectivelyto said high frequency and the'frequency of saidperiodic variations, said means comprising acontrol element having a different, form in 1ts varlous portlons, operable to determine the tuning of said respective ciI' cuitsin accordance with its form atsaid various portions. I I ,v

8. An apparatus for receiving radianirenergy having a high carrier frequency and having periodic variations impressed there on of 'a frequency lower than said carrier frequency but above good audibility, comprisingcircuits connected together in cascade relation, a detector interposed between said c1rcu1ts,-var1able condensers lncludedm said circuits respectively'and means for adjusting- ,said condensers to tune said circuitsto sald carl ler frequency andsald lower frequencyrespectively, comprising a key provided with indentations and means'for setting the 'condensers in accordance with the depths of the indentations in the key. I

9. An apparatus for receiving radiant energy having a high carrier frequency and having periodic. variations impressed .thcre-.

on of a frequency lower than saidcarrier free quency but) above good audibility, comprising a detector, a resonant circuit, connected withthe inputsside of said. detector and tuned i said detectors arid tuned to said lower frequenc'y, an indicator, contacts arranged normally to close a circuit through the indie cater and the output cireuit'of the first-' mentioned detector, and means for connecting said detectors in cascade relation, in-' cluding devices operable to cut said indicator out of the circuit of the first-mentioned detector and to connect the indicator in theoutput circuit-oi said second detector.

' cade relation, including devices operable to X I cut said 1I1d1t3l lLOI"0lll] of the output circuit.

of the first-mentioned detector and to connect the indicator in the output circuit of said second detector, and meanscont'rolled by certain of said devices for tuning said resonant circuits respectively to said higher and lower frequencies. a

11. An apparatus for receiving radiant energy having a high carrier frequency and having periodic variations impressed thereon of a frequency lower than said carrier frequency but above good audibility, comprising a detector, a resonant circuit connected with the input side of said detector, a second I detector, and a second resonant circuit interposed between 'said detectors, an indicator, contacts arranged normally to close a circuit through the indicator and the output circuit of the first-mentioned detector, ,means --for.

connecting said detectors in cascade relation,

including a key operable to cut said indicas tor 'out of the circuit of the first-mentioned detector and toiconnect the indicator with the output circuit. of the second detector,-

and means controlled by said key for tuntive frequency characteristics of the 'wave without knowledge by the operator of said :l'requency eharacleristies, said means comprising a separable control element comprising portions formed to set the tuning clements so as to be in resonance with the respective frequency clm-raeteristics of the wave.

13. A receiving apparatus for radiant energy comprising a variable \rondenser ineluding a rotatable shalt, a sleeve mounted on.the shaft, plates carried by the sleeve, means for securing the sleeve to the shaft in various positionsrelatively thereto (,'()!l'lprising a member keyed to the shaft at one end of the sleeve and a nut. threaded on the shaft. and means for rotating the shaft to adjust lhe condenser.

1-1. A receiving apparatus for radiant energy .eonipl'ising a variable condenser including-a rotatable shaft, a sleeve mounted on the shaft, plates carried by the sleeve, devices for securing the sleeve to the shaft in various positions relatively tl'iereto, indicators mounted for movement with said sleeve and with said shal'trelatively to the sleeve respectively, and a separable member, having a different form in its various portions, for controlling the rotation of the shaft and consequent adjustment of the condenser in "accordance with the form of said separable member at its various portions. I

15. In a radio station finder, in combination, with the tuning instrument of a receiving set, apinion upon, the shalt of" said in- "strumcnt, a vertical spring actuated rack in signature.

ALBERT D. TRENOR. 

